Ground-enhanced electrical connector

ABSTRACT

An electrical connector with enhanced grounding characteristics which reduce the possibility of signal transmission error includes a connector housing formed from an electrically insulative material, a plurality of conductive terminals mounted on the connector housing, the terminals having tail portions which extend out of and away from the connector housing for attachment to a printed circuit board. A conductive grounding plate, in the form of a metal shield, is mounted to the exterior of the connector housing The grounding plate incudes at least one grounding terminal integrally formed therewith at extending outwardly therefrom at the level of the connector conductive terminals in a space between two adjoining conductive terminals.

BACKGROUND OF THE INVENTION

The present invention relates generally to electrical connectors foreffecting reliable connections between printed circuits, and morespecifically, to electrical connectors having enhanced groundingcharacteristics which increase the suitability of the connectors for usein high speed and high-frequency signal applications.

When an electrical connector is used to connect together high-frequencysignal circuits of printed circuit boards, or a printed circuit boardand a conductive wire together, a metal grounding plate is utilized aspart of the connector to prevent external leakage of the high-frequencycircuits at the connector. The grounding plate is located on theexterior on the insulated housing of the connector as described inJapanese Unexamined Patent Publication No. 5-217630 and JapaneseUnexamined Patent Publication No. 6-84568, for example. These typeconnectors utilize an insulative housing, a plurality of terminalsmounted within the insulative housing and a conductive metal groundingplate attached to the exterior of the insulative housing. Across-sectional view of these connectors would reveal, in essence, a"sandwich" type structure where the insulative housing is held, orsandwiched, between the connector terminals and the grounding plate. Insuch a construction, the terminals tend to act as capacitors and when ahigh-frequency signal is applied to a particular terminal, that signalmay tend to "jump" through or across the insulative housing as well asany adjacent air gap to the metal grounding plate. This phenomenon iscommonly referred to in the art as capacitive coupling. The groundingplate is connected at opposite ends of the connector to groundingcircuits so that any signals which are coupled to the grounding platewill pass to a groundpath and not pass to any other terminals in theconnector.

However, when the high-frequency signals jump to the grounding plate andseek the grounding circuits connected thereto at the ends of theconnector, the possibility exists, especially when the length of theconnector is increased, that the high-frequency signal may radiate as ittravels the length of the connector to the ground circuits thereat. Thisis known as an "antenna effect" because the grounding plate acts as anantenna and the high-frequency signals may jump or be coupled back toother terminals of the connector, resulting in mistransmission andsignal error that is detrimental to the operation of the circuits and ofthe connector.

In the aforementioned connectors, grounding terminals are integrallyformed with the grounding plate and are located at opposite ends of theconnector in the longitudinal directions, so as not interfere with thesolder tail portions of the connector terminals. As the length of theconnector is increased, the number of terminals are also increased andthe length of the antenna locally formed in the grounding plate asexplained above also increases, which in turn, increases the possibilityof erroneous transmission of high frequency signals to other terminalsof the connector.

SUMMARY OF THE INVENTION

The present invention provides a solution to the problems set forthabove. It is an object of the present invention to provide an electricalconnector with enhanced grounding capability in the grounding plate thatreduces the likelihood of detrimental leakage of high-frequency signalsfrom occurring.

In order to accomplish this and other objects, an enhanced groundingconnector constructed in accordance with one aspect of the presentinvention, comprises an insulative housing, a plurality of terminalsmounted within the insulative housing, the terminals having solder tailportions of the terminals extending externally from connector near thebottom surface of the housing, a conductive grounding plate mounted onthe exterior of the housing, and the grounding plate having at least onegrounding terminal disposed in proximity to the high-frequency signalcircuit and between the solder tail portions of the terminal.

The tail portions of the terminals and the grounding terminals of thegrounding plate are preferably aligned together so that they lie flushin substantially the same horizontal plane and the respective circuitboard mounting surfaces thereof are coplanar. The grounding plate may beprovided with additional grounding terminals at both ends thereof aswell as at along intermediate portions of the grounding plate where thegrounding terminals are arranged between a plurality of the connectorconductive terminals.

The grounding terminals are formed in the grounding plate by anappropriate method, such as stamping and forming, which avoids the needfor providing ground terminals within the conductive terminals of theconnector, thereby permitting the present invention with connectors ofgreater circuit numbers. Also, by forming the grounding terminals in thegrounding shield, the grounding terminals may be made to lie insubstantially the same plane as the connector circuit terminals tomaintain the coplanarity of all of the terminals of the connector, whichreduces mounting errors encountered in attaching the connector to aprinted circuit board.

These and other objects, features and advantages of the presentinvention will be clearly understood through a consideration of thefollowing detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

In the course of the following description of the detailed description,reference will be made to the attached drawings wherein like referencenumerals identify like parts and wherein:

FIG. 1 is a plan view of a receptacle-style electrical connectorconstructed in accordance with the principles of the present invention;

FIG. 2 is a front elevational view of the electrical connector of FIG. 1taken along lines 2--2 thereof;

FIG. 3 is an end elevation of the electrical connector of FIG. 1 takenalong lines 3--3 thereof;

FIG. 4 is a plan view of a plug-style electrical connector with enhancedgrounding characteristics constructed in accordance with the principlesof the present invention;

FIG. 5 is a frontal elevational view of the connector of FIG. 4 takenalong lines 5--5 thereof;

FIG. 6 is a side elevational view of the connector of FIG. 4 taken alonglines 6--6 thereof; and

FIG. 7 is an enlarged sectional view of the receptacle and plug-styleconnectors of FIGS. 1 and 4 engaged together.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 to 3 illustrate a receptacle-style is electrical connectorcomponent with enhanced grounding characteristics and constructed inaccordance with the present invention, generally indicated at 1. Theconnector component 1 includes an elongated connector housing 2,preferably formed from an electrically insulative material. A pluralityof conductive terminals 3 are disposed within the insulative housing 2and arranged in two aligned rows 30, 32, preferably parallel within arecess 34 that extends longitudinally with the housing 2 betweenopposing ends 36, 38 of the connector component 1. The recess 34 isenclosed by a surrounding wall 5 of the connector component. Aconductive grounding plate 4, in the form of a shield, is mounted on theexterior of the housing 2 and the shield 4 surrounds the outer peripheryof the housing 2.

The terminals 3 of the connector component 1 can be seen to includeengagement or contact portions 40 which lie along interior surfaces ofthe walls 42 of the pedestal 44 in the recess 34 and which extendfurther down along the housing sidewalls 5 toward the bottom 6 of thehousing 2. (FIG. 7.) Solder tail portions 7 of the terminals are joinedto the contact portions 40 and extend outwardly from the connector alongthe bottom surface 6 in a generally horizontally plane beyond the sidesof the housing 2 along the two opposite sides of the connector component1.

The terminals 3 of each row are maintained in a predetermined spacing"S" at given intervals. Wider spacing intervals 8 are provided betweenadjoining terminals at particular locations, corresponding in thepreferred embodiment depicted, to every Nth terminal. These secondspacing intervals 8 separate the conductive terminals 3 of the connector1 into discrete groups of terminals (and solder tail portions 7).Coincident with these intervals 8, the grounding plate 4 is providedwith grounding terminals 9 (FIG. 2) formed along its lower edge 4a atthe level of the conductive terminal solder tail portions 7. Thesegrounding terminals 9 have general L-shaped configurations and take theform of horizontal lugs which are interposed between the groups ofconductive terminals in the wider spacing intervals 8. Each suchgrounding terminal 9 or lug, also includes a circuit board engagementportion 9a, preferably planar in configuration, that extends outwardlyand lies in a common plane with the solder tail portions 7 of theconnector conductive terminals 3. Thus, the bottom surfaces of theconductive terminal solder tail portions 7 and the grounding terminals 9will preferably be coplanar so that the connector may be mounted on anassociated printed circuit board 46 by conventional surface soldering.

The connector component grounding shield 4 may also include secondarygrounding terminals 10 of a greater width than the grounding terminals 9so that these terminals 10 assist in firmly mounting the connectorcomponent 1 to the printed circuit board by soldering. The groundingshield 4 is preferably stamped and formed from sheet metal stock todefine, as illustrated in the preferred embodiment of FIGS. 1-7, twoopposing, substantially planar body portions 50 with retention flanges52 disposed at their opposite ends that are folded down and over into afirm holding engagement with the connector component housing 2. The bodyportions 50 may include a series of engagement tabs 54 formed thereinwhich extend slightly inwardly into frictional engagement with theconnector component housing 2.

FIGS. 4 to 6 illustrate a preferred embodiment of a plug-styleelectrical connector 11 with enhanced grounding characteristics which isengageable with the receptacle connector 1 described above. Similar toconnector component 1, the plug-style connector 11 includes an elongatedconnector housing 12 formed from an insulative material and a pluralityof terminals 13 disposed thereon with solder tail portions 17 extendingfrom the bottom 16 of the connector component 11. It further includes anexterior conductive grounding plate 14 in the form of a metallicgrounding shield. The terminals 13 are aligned in two separate rowsalong the longitudinal extent of the housing 12 so as to oppose, andengage, corresponding opposing terminals 3 of the receptacle-styleconnector component 1. The terminals 13 in each row are spaced apartfrom each other at a first predetermined spacing "S" and include secondpredetermined spacings or intervals 18, which are wider than the firstspacing. The grounding plate 14 is provided with a plurality ofgrounding terminals 19 corresponding in number to the number of secondspacing intervals and which are disposed at locations thereoncorresponding to these wider spacing intervals 18.

These grounding terminals 19 extend in these wide intervals 18 and arealso preferably positioned in both the horizontal and verticaldirections so that their bottom planar engagement surfaces 19a will liein the same horizontal plane as the planar engagement surfaces 17a ofthe connector component conductive terminals 13 in order to maintaincoplanarity of both the grounding and conductive terminals of theconnector component as well as alignment with opposing contact pads ofgrounding circuits of an associated circuit board. On opposite ends ofthis connector component 11, grounding terminals 20 which are largerthan the grounding terminals 19 are provided for the purpose explainedabove.

FIG. 7 is a sectional view of a receptacle-type connector component 1and a plug-type connector component 11 interengaged together. In thisengagement, the terminals 3 and 13 of the two connector components 3, 13contact each other in an electrically conductive fashion. The groundingplate 14 of the plug-type connector 11 engages the inside of the groundplate 4 of the receptacle-type connector component 1 at the engagementend 15 thereof. A conductive engagement projection 21 which is formedinside of the grounding plate 4 engages the grounding plate 14 so thatthe two grounding plates 4 and 14 are connected electrically together.

In the illustrated embodiment, when high frequency voltage is applied toany one of the terminals 3 and 13, the high frequency current that jumpsor which is induced alongside the connector components 1, 11 by way ofcapacitive coupling in the exterior grounding plates 4, 14 will flowtoward the closest groundpath. The nearest groundpaths are provided bythe grounding terminals 9, 19 integrally formed and can be fed to thegrounding circuits of the circuit board(s) 46 through the groundingterminals 9 and 19. Accordingly, the distance which the high frequencycurrent signals that are locally formed in the grounding plates 4, 14 ismade as short as possible. When a specific number N of groundingterminals 9, 19 is used and the grounding terminals 9, 19 are spaced atequal intervals along the length of the connector 1, 11, this distanceto ground for a signal is no greater than 1/N+1 times the length of theconnector 1, 11. Therefore, the likelihood of an antenna effectoccurring for the conductive terminals 3, 13 is substantially reduced,in not virtually eliminated. As a result, erroneous signal transmissionto other terminals 3 and 13 is likewise substantially reduced, whichincreases the reliability of the ground-enhanced connectors 1 and 11 ofthe present invention.

It will be understood that position and number of the groundingterminals 9 and 19 provided in each grounding plates 4, 14 is notrestricted to that shown in the preferred embodiment illustrated. Sincethe antenna effect can be avoided by providing grounding terminals 9 and18 in the vicinity of the connector conductive terminals 3, 13, to whichthe high frequency current is applied, when number of the terminals 3,13, which are to be applied the high frequency current is few, thenumber of grounding terminals 9, 19 may be few, as well.

By arranging at least one of the grounding terminals 9, 19 to be locatedbetween any conductive terminals 3, 13, which carry high-frequencysignals, the formation of the antenna effect can be avoided. On theother hand, when number of the terminals 3, 13 to which high-frequencycurrent is applied is large, the number of grounding terminals 9, 19 canbe increased accordingly from that shown in the preferred embodiment.

Although the solder tail portions 7, 17 and grounding terminals 9, 19shown in the preferred embodiment extend parallel to the bottom surfaces6, 16 of the connector housings 2, 12 for surface soldering, it will beunderstood that the solder tail portions 7, 17 and the groundingterminals 9, 19 may extend from the housing perpendicular to the bottomsurfaces 6, 16 thereof so as to enable dip soldering by inserting intothe terminals through holes formed in the printed circuit board.

As set forth above, with the grounding enhanced electrical connector ofthe present invention, the high frequency current induced in themetallic grounding plate can be fed to the grounding circuit through ashort path for enhancing the grounding function of the metallicgrounding plate. Therefore, erroneous signals will never be transmittedto improve reliability of the electrical connector. And further, becausethe grounding terminals are directly connected to contact pads on theprinted circuit board, the need to connect the grounding terminals tospecific conductive terminals of the connector, either interior orexterior of the connector housing, is eliminated, thereby decreasing thecost of manufacture of the connector.

Although the invention has been illustrated and described with respectto exemplary embodiment thereof, it should be understood by thoseskilled in the art that the foregoing and various other changes,omissions and additions may be made therein and thereto, withoutdeparting from the spirit and scope of the present invention. Therefore,the present invention should not be understood as limited to thespecific embodiment set out above but to include all possibleembodiments which can be embodied within a scope encompassed andequivalents thereof with respect to the feature set out in the appendedclaims.

We claim:
 1. In an electrical connector having an elongated housing withat least one housing wall formed from an electrically insulativematerial and a plurality of electrically conductive terminals mounted onthe connector housing, the conductive terminals having solder tailportions extending out of and away from said connector housing along anextent of said housing wall, said solder tail portions being spacedapart from each other in a first predetermined spacing, said connectorfurther having an electrically conductive grounding plate mounted onoutside of said connector housing and extending along said housing wallextent, the improvement, comprising:at least one primary groundingterminal integrally formed in said grounding plate at the level of saidconductive terminal solder tail portions, and said conductive terminalsolder tail portions being arranged in at least two discrete groupsspaced apart from each other in a second predetermined spacing to definea grounding space that separates said two discrete groups of conductiveterminal solder tail portions, the grounding space receiving saidprimary grounding terminal therein.
 2. A connector as set forth in claim1, wherein said conductive terminal solder tail portions and saidprimary grounding terminal lie in substantially the same plane.
 3. Aconnector as set forth in claim 1, wherein said grounding plate includessecondary grounding terminals at opposite ends of said connectorhousing, said primary grounding terminal being disposed on saidgrounding plate intermediate said secondary grounding terminals.
 4. Aconnector as set forth in claim 1, wherein said grounding plate includesa plurality of primary grounding terminals integrally formed in saidgrounding plate at the level of said conductive terminal solder tailportions, said conductive terminal solder tail portions including a likeplurality of grounding spaces, each of which receives a single primarygrounding terminal therein.
 5. A connector as set forth in claim 2,wherein each of said conductive terminal solder tail portions and saidprimary grounding terminals have respective planar circuit boardengagement surfaces, said respective circuit board engagement surfaceslying in a substantially common horizontal plane.
 6. A connector as setforth in claim 1, wherein said grounding plate includes means forfrictionally engaging exterior surfaces of said connector housing.
 7. Aconnector as set forth in claim 6, wherein said frictional engagementmeans includes at least one engagement tab formed in a body portion ofsaid grounding plate.
 8. A connector as set forth in claim 4, whereinsaid primary grounding terminals are spaced along the length of saidconnector at equal intervals.
 9. A connector as set forth in claim 4,wherein said connector includes N primary grounding terminals spacedlongitudinally in equal intervals along said grounding plate to define Ngroundpaths, whereby the shortest distance which any signal carried bysaid connector conductive terminals has to travel to reach one of saidgroundpaths by way of capacitive coupling through said connector housingis no greater than 1/N+1 times the length of said connector.
 10. Aconnector as set forth in claim 1, wherein said grounding plate isformed from a sheet metal blank having two parallel longitudinal sideportions and two transverse end portions, the transverse end portionsbeing folded into contact with said side portions to define a hollowenclosure which receives said connector housing therein.
 11. A connectoras set forth in claim 10, wherein said grounding plate side and endportions are integrally formed together in a single sheet metal blank.12. A connector with enhanced grounding characteristics, the connectorcomprising an elongated housing formed from an electrically insulativematerial, the connector housing having an interior portion containing aplurality of electrically conductive terminals, the conductive terminalseach having a contact portion disposed within said connector housinginterior portion and a solder tail portion extending out of and awayfrom said connector housing at a level for engagement with a printedcircuit board, said conductive terminal solder tails portions furtherbeing disposed along a length of said connector in discrete sets byintervening spaces, said connector further including an electricallyconductive grounding plate disposed on said connector housing such thatportions of said connector housing lie between said grounding plate andsaid conductive terminals, said grounding plate including a plurality ofgrounding terminals formed therein and extending away from saidconnector housing at said circuit board engagement level and interposedbetween selected pairs of said discrete sets of said conductiveterminals, said grounding terminals extending into said interveningspaces thereby defining a plurality of groundpaths for signals coupledfrom said conductive terminals to said grounding plate.
 13. Theconnector of claim 12, wherein said grounding plate includes a metalgrounding shield, the grounding shield including means for frictionallyengaging an exterior surface of said connector housing.
 14. Theconnector of claim 12, wherein said conductive terminal solder tailportions are disposed in a series of preselected groups along the lengthof said connector at a first predetermined spacing and said groups ofconductive terminals solder tail portions are spaced apart from eachother by a second predetermined spacing which is greater than said firstpredetermined spacing, said grounding terminals being received withinsaid second predetermined spacing and being interposed between twoadjacent groups of said conductive terminals.
 15. The connector of claim12, wherein each of said grounding terminals extends away from saidconnector housing in a common plane with said conductive terminal soldertail portions.
 16. The connector of claim 12, wherein said groundingplate includes a plurality of engagement tabs adapted to frictionallyengage exterior surfaces of said connector housing.
 17. The connector ofclaim 12, wherein said connector housing interior portion includes anelongated recess and said conductive terminals are disposed along twoopposing sides of said recess.
 18. The connector of claim 12, whereinsaid grounding terminals are integrally formed in said grounding plateat substantially the same level at which said conductive terminal soldertail portions extend out of said connector housing.
 19. The connector ofclaim 12, wherein said connector interior portion is enclosed by aplurality of connector housing walls and said grounding plate includes ahollow enclosure which overlies said connector housing walls.
 20. Anelectrical connector comprising: an elongated connector housing formedfrom an electrically insulative material, the connector having aplurality of electrically conductive terminals disposed therein, saidconnector housing having a plurality of walls which define exteriorsurfaces of said connector and which define an interior recess of saidconnector, said conductive terminals having contact portions disposedwithin said recess and circuit board attachment portions which extendaway from said connector exterior surfaces, said connector furtherincluding an electrically conductive grounding shield which overlies atleast one exterior surface of said connector in opposition to a group ofsaid conductive terminals such that said conductive grounding shield andsaid group of conductive terminals are separated by one of saidconnector housing walls, said conductive terminal attachment portionsbeing segregated into discrete arrays along the length of said connectorby intervening grounding spaces, said grounding shield including aplurality of grounding terminals formed integrally therewith andextending outwardly therefrom away from said connector housing exteriorsurfaces, said grounding terminals being received within said groundingspaces and interposed between adjacent arrays of said conductiveterminal attachment portions.
 21. The connector of claim 20, whereinsaid conductive terminal attachment portions and said groundingterminals each include circuit board attachment faces which aresubstantially disposed in a common plane.
 22. The connector of claim 20,wherein said grounding shield includes two longitudinal body portionsand two transverse end portions which cooperate to define a hollowshielding enclosure which overlies said connector housing exteriorsurfaces.
 23. A connector with enhanced grounding characteristics, theconnector comprising an elongated housing formed from an electricallyinsulative material, the connector housing having an interior portioncontaining a plurality of electrically conductive terminals, theconductive terminals each having a contact portion disposed within saidconnector housing interior portion and a solder tail portion extendingout of and away from said connector housing at a level for engagementwith a printed circuit board, said connector further including anelectrically conductive grounding plate disposed on said connectorhousing such that portions of said connector housing lie between saidgrounding plate and said conductive terminals, said grounding plateincluding a plurality of grounding terminals formed therein andextending away from said connector housing at said circuit boardengagement level and interposed between selected pairs of conductiveterminals, said grounding terminals defining a plurality of groundpathsfor signals coupled from said conductive terminals to said groundingplate, said conductive terminal solder tail portions being disposed in aseries of groups along the length of said connector at a firstpredetermined spacing, said groups of conductive terminals solder tailportions being spaced apart from each other by a second predeterminedspacing which is greater than said first predetermined spacing, saidgrounding terminals being received within said second predeterminedspacing and being interposed between two adjacent groups of saidconductive terminals.
 24. An electrical connector comprising: anelongated connector housing formed from an electrically insulativematerial, the connector having a plurality of electrically conductiveterminals disposed therein, said connector housing having a plurality ofwalls which define exterior surfaces of said connector and which definean interior recess of said connector, said conductive terminals havingcontact portions disposed within said recess and circuit boardattachment portions which extend away from said connector exteriorsurfaces, said connector further including an electrically conductivegrounding shield which overlies at least one exterior surface of saidconnector in opposition to a group of said conductive terminals suchthat said conductive grounding shield and said group of conductiveterminals are separated by one of said connector housing walls, saidconductive terminal attachment portions being segregated into discretearrays along the length of one of said walls of said connector byintervening grounding spaces, said grounding shield including aplurality of grounding terminals formed integrally therewith andextending outwardly therefrom away from said connector housing exteriorsurfaces, said grounding terminals being received within said groundingspaces and interposed between adjacent arrays of said conductiveterminal attachment portions.